This invention generally relates to controls for electronic devices that need to be awakened out of a sleep mode where wake up time is limited. More particularly, this invention relates to a unique switching strategy within a wake up system for such electronic devices.
Modern day vehicles include a variety of electronic components. The power consumption of all of these components can prove to be too much and designers are constantly facing the challenge of reducing power consumption while, at the same time, providing the same or enhanced options on a vehicle. One way of managing power consumption is to have various peripheral devices enter a sleep mode when the device is not in use.
There are a variety of strategies for causing such devices to enter a sleep mode and for waking up the devices as needed. Typical arrangements include a linear voltage regulator, which introduces expense. Cost-savings are a critical concern in automotive applications. Another difficulty with conventional approaches is that they are not universally applicable and cannot meet some of the more stringent requirements regarding parasitic leakage current and limited wake up times. This difficulty is particularly present in devices where an energy reserve is part of a power supply to boost a battery voltage to a higher voltage level for powering the electronics of a particular device.
In one example, the parasitic leakage current when a device is in sleep mode must be less than or equal to 500 micro amps. It is desirable to provide an arrangement that satisfies the low leakage current requirements, is versatile enough to be useful with a variety of devices, facilitates a fast wake up response and is cost effective to implement. This invention addresses those needs while avoiding the shortcomings of prior arrangements.